System and method for controlling thermal characteristics of an inkjet printhead

Abstract

A printing system having a printhead assembly with an integrated distributive processor that provides localized control of the thermal characteristics of a printhead. The printing system includes a controller, a power supply and a printhead assembly. The printhead assembly includes a memory device and distributive processor integrated with an ink driver head. The printhead assembly includes a system and method for measuring thermal characteristics of the printhead, providing feedback to control devices including the distributive processor and making control decisions based upon the measure thermal characteristics.

What is claimed is:  
     
       1. A thermal control system for a printhead assembly with an ink ejection driver head, comprising: 
       a sensor coupled to the ink ejection driver head that generates a measured signal;  
       a distributive processor physically integrated with the ink ejection driver head and having a converter that generates a digital format of the measured signal and registers for storing temperature-related information; and  
       a thermal control device that analyzes the digital format and the temperature-related information and makes thermal control decisions for regulating thermal characteristics of the ink ejection driver head.  
     
     
       2. The thermal control system of  claim 1 , wherein the sensor has a voltage output proportional to a sensed temperature. 
     
     
       3. The thermal control system of  claim 1 , wherein the converter is a digital to analog converter having a digital input and a converter voltage output proportional to a value of the digital format received by the digital input. 
     
     
       4. The thermal control system of  claim 1 , further comprising a counter having an output connected to the converter and operable to increment the digital format. 
     
     
       5. The thermal control system of  claim 4 , wherein the counter includes a storage register for storing the digital format. 
     
     
       6. The thermal control system of  claim 4 , wherein the counter is responsive to an equivalency signal for transmitting the digital format. 
     
     
       7. The thermal control system of  claim 1 , further comprising a temperature control device for comparing the digital format to a preselected temperature threshold value to determine if the temperature is within a selected range, and for changing the temperature in response to a determination that the temperature is outside of the selected range. 
     
     
       8. The thermal control system of  claim 7 , wherein changing the temperature comprises transmitting energy to the printhead assembly. 
     
     
       9. The thermal control system of  claim 7 , wherein changing the temperature comprises preventing printing. 
     
     
       10. The thermal control system of  claim 7 , wherein the temperature control device includes a setpoint register containing the preselected value, a sensor register containing the digital format, and a comparator connected to the setpoint register and to the sensor register. 
     
     
       11. The thermal control system of  claim 1 , further comprising a reference voltage connected to the converter. 
     
     
       12. The thermal control system of  claim 1 , further comprising a distributive processor incorporating the converter, analyzing the digital format and making thermal control decisions. 
     
     
       13. A printing system including the printhead assembly of  claim 1 , and further comprising: 
       a media moving mechanism;  
       a printhead support mechanism that supports the printhead assembly in relation to the media moving mechanism;  
       an ink supply coupled to the printhead assembly for providing ink to the printhead assembly; and  
       an external controller that receives the digital format.  
     
     
       14. An inkjet printing system comprising: 
       a sensor;  
       a controller; and  
       a printhead assembly having an ink ejection driver head that is in communication with the controller and the sensor, the ink ejection driver head including a distributive processor physically integrated with the ink ejection driver head, wherein the distributive processor includes registers for storing temperature-related information and a thermal control device for regulating thermal characteristics of the printhead assembly.  
     
     
       15. The inkjet printing system of  claim 14 , further comprising an ink supply for providing ink to the printhead assembly. 
     
     
       16. The inkjet printing system of  claim 14 , wherein the ink supply is a removeably mounted ink container. 
     
     
       17. The inkjet printing system of  claim 14 , further comprising a primitive having a plurality of nozzles for ejecting the ink supplied by the ink supply. 
     
     
       18. The inkjet printing system of  claim 14 , further comprising: 
       a media moving mechanism;  
       a printhead support mechanism that supports the printhead assembly in relation to the media moving mechanism; and  
       an ink supply coupled to the printhead assembly for providing ink to the printhead assembly.  
     
     
       19. The inkjet printing system of  claim 14 , wherein the thermal control device regulates the thermal characteristics of the printhead assembly by comparing a measured signal of the sensor to a preselected temperature threshold value to determine if the temperature is within a selected range, and changing the temperature in response to a determination that the temperature is outside of the selected range. 
     
     
       20. The inkjet printing system of  claim 19 , wherein changing the temperature comprises transmitting energy to the printhead assembly. 
     
     
       21. The inkjet printing system of  claim 19 , wherein changing the temperature comprises preventing printing. 
     
     
       22. The inkjet printing system of  claim 19 , wherein the temperature control device includes a setpoint register containing the preselected value, a sensor register containing the measured signal, and a comparator connected to the setpoint register and to the sensor register. 
     
     
       23. A printing method for a printhead assembly having an ink ejection driver head, comprising: 
       generating a measured signal from the printhead assembly in a digital format;  
       storing temperature-related information in registers physically integrated with the ink ejection driver head of the printhead assembly; and  
       using a distributive processor physically integrated with the ink ejection driver head that uses the digital format and the temperature-related information for regulating thermal characteristics of the printhead assembly.  
     
     
       24. The printing method of  claim 23 , further comprising: 
       comparing the measured signal to a preselected temperature threshold value;  
       determining if the temperature is within a selected range; and  
       changing the temperature in response to a determination that the temperature is outside of the selected range.  
     
     
       25. The printing method of  claim 24 , wherein changing the temperature comprises transmitting energy to the printhead assembly.